Steviol glycoside aggregate, and preparation method therefor and use thereof

Abstract

A steviol glycoside aggregate, having a fibrous structure assembled from steviol glycosides. The steviol glycosides comprise the following components in percentage by mass: stevioside or / and rebaudioside A: 80-99.9%; and another steviol glycoside: 0.1-20%. The preparation method comprises the following steps: adding water to dissolve steviol glycosides to prepare a steviol glycoside solution having a mass fraction of 0.5-30%, carrying out assembly under the conditions of a temperature of 10-80°C and standing or mechanical disturbance, and then carrying out centrifugation and drying, thereby obtaining the steviol glycoside aggregate. The steviol glycoside aggregate can be used as a sweetener in foods.

Description

A kind of stevioside aggregate and its preparation method and application Technical Field

[0001] The present invention relates to the technical field of food additives, and in particular to a steviol glycoside aggregate, a preparation method and an application thereof. Background Art

[0002] Steviosides are a class of diterpene glycosides extracted from the stevia leaf. They are characterized by high sweetness (200 to 400 times that of sucrose) and low energy (1 / 300 of sucrose). They also possess a wealth of biological activities (e.g., preventing dental caries, lowering blood pressure and blood lipids, combating lipid peroxidation, and regulating intestinal flora). They have become the most widely used natural sweetener on the market. Currently, over 32 steviol glycoside components have been discovered, with stevioside and rebaudioside A being the two most important, accounting for approximately 90% of the total steviol glycoside content.

[0003] Stevioside has a pronounced bitterness, making it difficult to use directly as a sweetener. To reduce its impact on the sweetness of steviol glycoside sweeteners, the production process typically requires the removal of stevioside from steviol glycoside sweeteners through separation and purification or specific enzymatic hydrolysis, or the enzymatic hydrolysis of stevioside into structures with enhanced sweetness. However, these methods suffer from high stevioside removal costs, resource waste, limited enzymatic hydrolysis conversion rates, and complex subsequent separation and purification processes. Rebaudioside A has a relatively pure sweetness, but at high concentrations, it can produce a bitter aftertaste and other unpleasant off-flavors. In recent years, several ingredients with sweetness superior to rebaudioside A have attracted attention. However, their extremely low concentrations in stevia, resulting in high extraction and use costs, and their extremely poor solubility in water (for example, rebaudioside B is 0.01% to 0.02%, rebaudioside D is approximately 0.04%, and rebaudioside M is approximately 0.26%), which significantly limits their application. Therefore, rebaudioside A remains the most mature and widely used steviol glycoside sweetener on the market.

[0004] In order to improve the sweetness of rebaudioside A and reduce its bitterness and other off-flavors, the existing methods are as follows:

[0005] 1) Mixing with other sweeteners, flavor enhancers, or bitterness masking agents (e.g., sugar alcohols, oligofructose, other artificial sweeteners, inulin, etc.) to achieve the effect of sweetening and masking bitterness, but this method will increase costs;

[0006] 2) Using microencapsulation technology to embed rebaudioside A in a shell structure, minimizing its bitterness by reducing the contact between its bitter structure and the bitter receptor proteins on the tongue (for example: using inulin, maltodextrin, etc. as encapsulating agents, and spray drying technology to encapsulate rebaudioside A; cross-linking whey protein and pectin to form a ternary composite microcapsule with rebaudioside A). However, microencapsulation not only masks the bitterness but also affects the sweetness, thus greatly limiting the product's use scenarios;

[0007] 3) Using bio-enzymatic hydrolysis technology to glycosylate rebaudioside A to obtain a new chemical structure, effectively improving the sweetness and taste, but this method is complex and has limited conversion rate, requires further separation and purification, and has high production costs;

[0008] 4) Rebaudioside A is chemically combined with other proteins to mask the bitter taste (for example, by coupling rebaudioside A with glycine or L-alanine). However, this method has harsh reaction conditions and requires the addition of some non-edible substances during the reaction, and its safety remains to be evaluated.

[0009] Therefore, it is of great significance to develop a stevioside aggregate with pure sweetness, less bitterness and odor, low cost and simple preparation process.

[0010] Summary of the Invention

[0011] The purpose of the present invention is to provide a steviol glycoside aggregate and a preparation method and application thereof.

[0012] The technical solution adopted by the present invention is:

[0013] A steviol glycoside aggregate having a fibrous structure assembled from steviol glycosides;

[0014] The steviol glycosides include the following components in percentage by mass:

[0015] Stevioside and / or rebaudioside A: 80%-99.9%;

[0016] Other steviol glycosides: 0.1% to 20%.

[0017] Preferably, the length of the steviol glycoside aggregates is 10 μm to 200 μm, and the diameter is 0.2 μm to 5 μm.

[0018] Preferably, the fibrous structure is at least one of a needle-like structure, a rod-like structure, and a stacked fiber cluster structure.

[0019] Preferably, the other steviol glycoside is at least one of rubusoside, rebaudioside B, rebaudioside D, rebaudioside E, rebaudioside M, dulcoside A, and steviolbioside.

[0020] Preferably, the steviol glycoside aggregates exhibit birefringence under a polarizing microscope.

[0021] A method for preparing the steviol glycoside aggregates as described above comprises the following steps: dissolving steviol glycoside in water to prepare a steviol glycoside solution with a mass fraction of 0.5% to 30%, then assembling at a temperature of 10°C to 80°C under static or mechanical disturbance conditions, and then centrifuging and drying to obtain the steviol glycoside aggregates.

[0022] Preferably, the dissolution is carried out at a temperature of 10° C. to 121° C., and the dissolution time is 2 min to 30 min.

[0023] Preferably, the dissolving is carried out at a stirring speed of 50 rpm to 1000 rpm.

[0024] Preferably, the pH of the steviol glycoside solution is 1.5 to 10.0.

[0025] Preferably, the steviol glycoside solution further contains at least one of inorganic salts, polysaccharides and proteins.

[0026] Preferably, the assembly is performed at a temperature of 20° C. to 60° C., under static or mechanical disturbance conditions.

[0027] Preferably, the mechanical disturbance is one of electromagnetic stirring at a stirring rate of 50 rpm to 1500 rpm, shear homogenization at a shear rate of 1000 rpm to 20000 rpm, and ultrasonic homogenization at a power of 25 W to 400 W.

[0028] Preferably, the assembly time is 0.5h to 120h.

[0029] Preferably, the centrifugation is carried out at a temperature of 4°C to 60°C, a centrifuge speed of 5000 rpm to 10000 rpm, and a centrifugation time of 5 min to 20 min.

[0030] Preferably, the drying method is one of freeze drying, natural drying, forced air drying, oven drying, spray drying, and fluidized bed drying.

[0031] A sweetener comprising the above-mentioned steviol glycoside aggregates.

[0032] A food comprising the above-mentioned steviol glycoside aggregates.

[0033] A method for improving the sweetness of steviol glycosides comprises the following steps: assembling steviol glycosides from structures without specific morphology into aggregates with a fibrous structure.

[0034] The structural formula of steviol glycoside in the present invention is as follows:

[0035] Stevioside:

[0036] Rebaudioside A:

[0037] Rubusoside:

[0038] Rebaudioside B:

[0039] Rebaudioside D:

[0040] Rebaudioside E:

[0041] Rebaudioside M:

[0042] Dulcoside A:

[0043] Stevioside:

[0044] The beneficial effects of the present invention are as follows: the steviol glycoside aggregates of the present invention have the advantages of pure sweetness, little bitterness and odor, low cost, simple preparation process, etc., and are suitable for large-scale production and application.

[0045] Specifically:

[0046] 1) The present invention modifies the sweetness of steviol glycosides by regulating molecular assembly to give them a more complex physical structure. Compared with the currently commonly used chemical and enzymatic methods of changing the molecular chemical structure, the obtained steviol glycoside products have better sweetness characteristics and less bitterness and odor;

[0047] 2) The preparation process of the steviol glycoside aggregates of the present invention is simple, the processing conditions are mild, the processing does not involve any organic solvents, the product yield is high, the carbon footprint is low and sustainable, and it is suitable for large-scale production applications;

[0048] 3) The steviol glycoside aggregates of the present invention have strong stability (under the conditions of a reconstitution temperature of 4°C to 60°C and a mass fraction of aggregates in the reconstituted solution of 0.001% to 5%, the aggregate structure can still be observed under a microscope), high safety, and a wide range of applications. They can be added to solid, semi-solid, and liquid foods in accordance with the requirements of "GB 2760-2014 National Food Safety Standard for the Use of Food Additives". BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 is a SEM image of commercially available stevioside.

[0050] FIG2 is a SEM image of commercially available rebaudioside A.

[0051] FIG3 is a microstructure diagram of sample 5 in Example 1 under an optical microscope (bright field).

[0052] FIG4 is a microstructure diagram of sample 7 in Example 1 under an optical microscope (bright field).

[0053] FIG5 is a microstructure diagram of sample 7 in Example 1 under a polarizing microscope.

[0054] FIG6 is a SEM image of control sample 2 in Example 6.

[0055] FIG7 is a SEM image of experimental sample 2 in Example 6. DETAILED DESCRIPTION

[0056] The present invention will be further explained and illustrated below with reference to specific embodiments.

[0057] Example 1:

[0058] Experiment on the preparation effect of stevioside aggregates under different preparation conditions:

[0059] Commercially available stevioside (powder, purity 95%) and commercially available rebaudioside A (powder, purity 99%) were added to water at a certain mass fraction, and then heated and dissolved at 100°C for 10 minutes to prepare a clear and transparent solution. The solution was then cooled to 25°C and assembled for 72 hours (the turbidity of the solution and its microscopic morphology under an optical microscope were used to determine whether aggregates were formed, with distilled water as the reference sample for turbidity). The solution was then centrifuged at 15°C and 8000 rpm for 20 minutes, and the solid obtained by centrifugation was placed in a cool and dry place to dry naturally. The experimental results of the preparation effect of stevioside aggregates under different preparation conditions are shown in the following table:

[0060] Table 1 Experimental results of the preparation effect of stevioside aggregates under different preparation conditions

[0061] Note:

[0062] Solution turbidity: Pipette a certain amount of solution into a quartz container and use an ultraviolet spectrophotometer to measure the absorbance of the sample at a wavelength of 660nm. The value is the turbidity of the solution.

[0063] Result analysis:

[0064] 1) The scanning electron microscope (SEM) images of commercially available stevioside and commercially available rebaudioside A in this example are shown in Figures 1 and 2.

[0065] As can be seen from Figures 1 and 2, stevioside is in the form of hollow spheres with a diameter of more than 30 μm, while rebaudioside A is in the form of blocks. The difference in the microscopic morphology of stevioside and rebaudioside A is mainly attributed to the drying process of steviol glycosides. Stevioside is dried by spray drying, and the atomized droplets instantly lose water at high temperature, resulting in the dried powder being hollow spheres. Rebaudioside A is dried by forced air, so the molecules are stacked together in the form of blocks. However, the surfaces of these two microstructures are smooth and flat, indicating that the molecules themselves do not have a special physical structure.

[0066] 2) The microstructure of sample 5 in this embodiment under an optical microscope (bright field) is shown in FIG3 , the microstructure of sample 7 under an optical microscope (bright field) is shown in FIG4 , and the microstructure of sample 7 under a polarizing microscope is shown in FIG5 .

[0067] From Figures 3 to 5 and Table 1, we can see that:

[0068] a) When the mass fraction of the steviol glycoside solution was greater than or equal to 0.5%, the turbidity of the solution increased after assembly for stevioside alone (samples 2-4), rebaudioside A alone (samples 6-8), and the composite solution with a stevioside and rebaudioside A mass ratio of 1:10 to 10:1 (samples 9-12), indicating the presence of aggregates in the solution. Furthermore, the higher the mass fraction of the steviol glycoside solution, the greater the turbidity value of the solution, indicating a greater amount of aggregates.

[0069] b) Observation under bright-field optical microscopy revealed no distinctive microscopic morphology in the solutions with no significant turbidity change (Samples 1 and 5) (Figure 3). However, in the solutions with significant turbidity changes, aggregates of fibrous or needle-like structures were observed. These aggregates were of varying sizes, ranging from approximately 0.2 μm to 5 μm in diameter and 10 μm to 200 μm in length (Figure 4).

[0070] c) Under polarized light, the aggregates exhibit significant birefringence (Figure 5);

[0071] d) Since steviol glycoside molecules are weakly acidic, the pH of the steviol glycoside solution is acidic, and as the steviol glycoside content increases, the pH value further decreases. However, this has no significant effect on the preparation of aggregates. During the assembly process, aggregates can be obtained under static / mild stirring (100 rpm to 300 rpm) conditions.

[0072] Example 2:

[0073] Experiment on the preparation effect of stevioside aggregates under different stevioside component conditions:

[0074] 1) Commercially available stevioside (powder, purity 95%) and commercially available rebaudioside A (powder, purity 99%) were mixed at a mass ratio of 3:1 and labeled as Stevioside 1;

[0075] 2) Commercially available rebaudioside B (powder), commercially available rebaudioside D (powder), and commercially available rebaudioside M (powder) were mixed at a mass ratio of 1:2:2 and labeled as Stevioside 2;

[0076] 3) Stevioside 1 and steviol glycoside 2 were mixed in a certain mass ratio and added to water so that the mass fraction of total steviol glycosides in the solution was 2%. The mixture was then heated and dissolved at 121° C. for 15 minutes and the pH of the solution was adjusted to 7.0 to prepare a clear and transparent solution. The solution was then cooled to 60° C. and homogenized at 3000 rpm for 1 hour for assembly. The mixture was then centrifuged at 25° C. and 10000 rpm for 5 minutes. The solid obtained by centrifugation was then freeze-dried. The experimental results of the preparation effect of steviol glycoside aggregates under different steviol glycoside composition conditions are shown in the following table:

[0077] Table 2 Experimental results of the preparation effect of stevioside aggregates under different stevioside component conditions

[0078] Note:

[0079] Yield of steviol glycoside aggregates: Yield (%) = (1-stevioside content in the supernatant after centrifugation of the solution) / amount of steviol glycoside added × 100%, wherein the determination of the steviol glycoside content in the supernatant after centrifugation of the solution refers to "GB 1886.355-2022 National Food Safety Standard Food Additive Stevioside".

[0080] It can be seen from Table 2 that the combination of high-content steviol glycoside 1 (stevioside and rebaudioside A) and low-content steviol glycoside 2 (rebaudioside B, rebaudioside D and rebaudioside M) can still form aggregates, and the yield increases with the increase in the proportion of steviol glycoside 2. When the mass proportion of steviol glycoside 2 reaches 25% (sample 5), the yield of aggregates is greatly improved, the aggregation rate is also faster, and the microstructure of the aggregates is more uneven. This may be because the water solubility of steviol glycoside 2 is poor, and its unstable existence in aqueous solution affects the formation of aggregates.

[0081] Example 3:

[0082] Experiments on the effects of other substances on the preparation of stevioside aggregates:

[0083] Commercially available stevioside (powder, purity 95%) and commercially available rebaudioside A (powder, purity 99%) were mixed in a mass ratio of 1:2 and added to water to make the mass fraction of total stevioside in the solution 4%. Other substances (inorganic salts, polysaccharides and proteins) were added, and then stirred and dissolved at 200 rpm at 20°C for 5 minutes, and the pH of the solution was adjusted to 6.5 to prepare a clear and transparent solution. The solution was then heated to 30°C and allowed to stand for 120 hours for assembly. The turbidity change of the solution during the standing period was recorded. The turbidity reference sample of the sample was a solution without stevioside added. The solution was then centrifuged at a temperature of 30°C and a centrifuge speed of 5000 rpm for 20 minutes. The solid obtained by centrifugation was then placed in an oven and dried at 60°C. The concentration of stevioside that did not form aggregates in the supernatant obtained by centrifugation was measured, and the aggregate yield was calculated. The experimental results of the effects of other substances on the preparation effect of stevioside aggregates are shown in the following table:

[0084] Table 3 Experimental results of the effects of other substances on the preparation of stevioside aggregates

[0085] From Table 3 we can see that:

[0086] a) Compared with the blank control sample (sample 1), when the steviol glycoside solution contained salt ions (samples 2-4), the solution formed aggregates faster;

[0087] b) As the ionic strength increases, the rate of aggregate formation in the steviol glycoside solution increases. However, after a 120-h preparation period, the yield of aggregates is similar to that of the blank control (Sample 1), indicating that the presence of salt ions in the steviol glycoside solution can accelerate aggregate formation but does not affect the yield.

[0088] c) After adding negatively charged polysaccharides to the stevioside solution (samples 5-7), the rate of aggregate formation slowed down, and with increasing system viscosity, the rate of formation further decreased. However, the aggregate yield was close to that of the blank control (sample 1). After adding positively charged polysaccharides (sample 8), the rate of aggregate formation slowed down, and the yield also decreased slightly (by 2.2%). For proteins, as the protein concentration in the system increased (samples 9-10), the rate of aggregate formation slowed down, and the yield further decreased. The degree of reduction in yield varied slightly with different types of proteins (samples 10-12).

[0089] In summary, the presence of other food components will affect the formation rate and yield of aggregates, but the change in yield is small (±2.7%). Therefore, it can be considered that aggregates can be prepared in solutions containing inorganic salts, polysaccharides, and proteins.

[0090] Example 4:

[0091] Experiment on the effect of pH on the preparation of stevioside aggregates:

[0092] Commercially available stevioside (powder, purity 95%), commercially available rebaudioside A (powder, purity 99%), and commercially available rebaudioside M (powder) were mixed in a mass ratio of 23:23:1 and added to water to make the mass fraction of total stevioside in the solution 1.5%. The mixture was then stirred and dissolved at 800 rpm at 10°C for 2 minutes, and the pH of the solution was adjusted to a certain value to prepare a clear and transparent solution. The solution was then subjected to ultrasonic homogenization at a temperature of 10°C and an ultrasonic power of 200 W for 0.5 hours for assembly. The mixture was then centrifuged at a temperature of 4°C and a centrifuge speed of 10,000 rpm for 30 minutes. The solid obtained by centrifugation was then dried in a blast drying oven at 45°C. The concentration of stevioside that did not form aggregates in the supernatant obtained by centrifugation was determined, and the aggregate yield was calculated. The experimental results of the effect of pH on the preparation effect of stevioside aggregates are shown in the following table:

[0093] Table 4 Experimental results on the effect of pH on the preparation of stevioside aggregates

[0094] As can be seen from Table 4, the pH of the stevioside solution is 1.5-10.0 (samples 1-4), which has no significant effect on the preparation of aggregates, indicating that this method is applicable to most food production scenarios (acidic, neutral, and alkaline).

[0095] Example 5:

[0096] Experiment on the effect of temperature on the preparation of stevioside aggregates:

[0097] Commercially available stevioside (powder, purity 95%) and commercially available rebaudioside A (powder, purity 99%) were mixed in a mass ratio of 1:5 and added to water to make the mass fraction of total stevioside in the solution 25%. The mixture was then stirred and dissolved at 300 rpm at 15°C for 10 min and the pH of the solution was adjusted to 3.0 to prepare a clear and transparent solution. The solution was then placed at different temperatures and allowed to stand for 72 h for assembly. The turbidity change of the solution during the standing period was recorded. The turbidity reference sample of the sample was distilled water. The mixture was then centrifuged at a temperature of 20°C and a centrifuge speed of 10,000 rpm for 5 min. The solid obtained by centrifugation was then placed in a drying cabinet and dried at a temperature of 18°C ​​and a relative humidity of 25% RH. The concentration of stevioside that did not form aggregates in the supernatant obtained by centrifugation was determined and the aggregate yield was calculated. The experimental results of the effect of temperature on the preparation effect of stevioside aggregates are shown in the following table:

[0098] Table 5 Experimental results on the effect of temperature on the preparation of stevioside aggregates

[0099] It can be seen from Table 5 that when the assembly temperature is 10℃~80℃ (samples 1~5), after 72h of static assembly, the yield of aggregates is relatively close, all above 90%, indicating that the temperature conditions at this time can be used for the production and preparation of aggregates; when the temperature reaches 90℃, the yield of aggregates is extremely low, indicating that the temperature is too high and is not conducive to the formation of aggregates; compared with sample 1 and sample 5, the turbidity values ​​of samples 2, 3, and 4 in the first 5h change more and the yield is higher, indicating that the formation rate and efficiency of aggregates are higher. Therefore, the preparation conditions of 20℃~60℃ are more conducive to the efficient production of aggregates.

[0100] Example 6:

[0101] Redissolution temperature experiment of stevioside aggregates:

[0102] Commercially available stevioside (powder, purity 95%) and commercially available rebaudioside A (powder, purity 99%) were mixed in a mass ratio of 1:5 as a control group, and Sample 3 in Example 5 was used as an experimental group. The samples were respectively added to water to make the mass fraction of stevioside in the solution 0.2%. The pH of the solution was adjusted to 7.0, and the solution was then stirred at different temperatures (500 rpm, 1 h). Subsequently, an appropriate amount of the solution was dripped onto a freshly peeled mica sheet. After natural drying at room temperature for 24 h, a scanning electron microscope was used to observe whether there was an aggregate structure on the mica sheet to study the effect of the re-dissolution temperature on the aggregate structure. The re-dissolution temperature experimental results of the obtained stevioside aggregates are shown in the following table (the SEM image of the control sample 2 is shown in FIG6 , and the SEM image of the experimental sample 2 is shown in FIG7 ):

[0103] Table 6 Experimental results of re-dissolution temperature of stevioside aggregates

[0104] As can be seen from Figures 6, 7 and Table 6, under the reconstitution conditions of this embodiment (0.2% stevioside, 4°C to 90°C, 500 rpm, 1 h), control samples 1 to 6 are commercially available stevioside samples. After the reconstitution solution was naturally dried, no special morphology was observed under scanning electron microscopy (Figure 6), that is, no aggregates were observed. However, the aggregate samples (experimental samples 1 to 5) still showed obvious aggregate morphology at the reconstitution temperature of 4 to 80°C (Figure 7), but at 80°C (experimental sample 5), the amount of aggregates in the field of view was greatly reduced compared with that at 4°C to 60°C (experimental samples 1 to 4), indicating that the temperature at this time may affect the stability of the aggregates in the solution. When the temperature was further increased to 90°C (experimental sample 6), no aggregates were observed in the field of view.

[0105] Example 7:

[0106] Redissolution concentration experiment of stevioside aggregates:

[0107] Sample 1 in Example 4 was added to water in a certain proportion so that the mass fraction of steviol glycoside in the solution was 0.001% to 5%. The pH of the solution was adjusted to 4.5, and the solution was placed at 20° C. and fully stirred (200 rpm, 3 h). Subsequently, an appropriate amount of the solution was dripped onto a freshly peeled mica sheet, and the mica sheet was then freeze-dried. A scanning electron microscope was used to observe whether there was an aggregate structure on the mica sheet to study the effect of the reconstitution solution concentration on the aggregate structure. The experimental results of the reconstitution concentration of steviol glycoside aggregates are shown in the following table:

[0108] Table 7 Experimental results of resolubilization concentration of stevioside aggregates

[0109] As shown in Table 7, when the aggregate powder is redissolved in water, the aggregate structure of all samples (0.001% to 5%) can be observed under a scanning electron microscope, indicating that the aggregate still exists as an aggregate structure when dispersed in water. It is worth noting that even at a concentration as low as 0.001%, its aggregate structure can still be observed under a microscope, indicating that the aggregate structure has extremely strong dilution stability and can meet the application requirements in most liquid products.

[0110] Example 8:

[0111] Liquid system sensory test:

[0112] Commercially available stevioside (powder, purity 95%), commercially available rebaudioside A (powder, purity 99%), Sample 3 and Sample 7 in Example 1 were dissolved in water to adjust the mass fraction of stevioside in the solution to 0.005% to 0.13%. The pH of the solution was adjusted to 6.5 and stirred thoroughly (300 rpm, 2 h). A sensory evaluation panel (30 people, including 16 women and 14 men, aged 22 to 36) evaluated the relative sweetness of the solution (using sucrose with a mass fraction of 10% as a reference sample), the minimum taste threshold (i.e., the minimum solution concentration at which a non-sweet taste is perceived), and the minimum bitterness threshold (i.e., the minimum solution concentration at which a bitter taste similar to quinine is perceived). The results of the liquid system sensory test are shown in the following table:

[0113] Table 8 Sensory test results of liquid system

[0114] As shown in Table 8, compared with commercially available stevioside, the stevioside aggregates prepared by the present invention have a relative sweetness increase of 45.69%, a minimum off-flavor threshold increase of 133.33%, and a minimum bitterness threshold increase of 80.95%. Compared with commercially available rebaudioside A, the rebaudioside A aggregates prepared by the present invention have a relative sweetness increase of 13.73%, a minimum off-flavor threshold increase of 135.71%, and a minimum bitterness threshold increase of 60.94%. Overall, the strategy of regulating the physical structure of steviol glycoside molecules adopted by the present invention has a significant sweetness modification effect. Compared with the unmodified aggregate structure, the prepared aggregate structure has a significantly improved sweetness and lower off-flavor and bitterness, that is, the sweetness is purer and can present a more refreshing sweetness like sucrose.

[0115] Example 9:

[0116] Semi-solid system sensory test:

[0117] Commercially available stevioside (powder, purity 95%) and commercially available rebaudioside A (powder, purity 99%) were mixed in a mass ratio of 1:2 as a control sample, and the aggregate of Sample 3 in Example 3 was used as an experimental sample. 2 g of stevioside, 240 g of milk powder, 4.8 g of monoglyceride, 7.2 g of gum arabic and 100 g of white sugar were weighed in sequence, mixed and added to 1680 g of water. After stirring until no obvious particles were present, 286 g of cream was added and stirred evenly to obtain a mixture, which was poured into an ice cream machine, whipped and frozen to obtain ice cream. Subsequently, a sensory evaluation panel (30 people, including 16 women and 14 men, aged 22 to 36) evaluated the stickiness, sweetness, sweetness persistence, bitterness and odor, and overall preference of the ice cream samples, with the full score set to 10 points. The sensory test results of the semi-solid system are shown in the following table:

[0118] Table 9 Semi-solid system sensory test results

[0119] Table 9 shows that compared to commercially available steviol glycosides, the ice cream prepared using the stevioside aggregates of the present invention showed little difference in viscosity and smoothness. In terms of sweetness, the experimental sample had a more intense sweetness perception, while the sweetness lasted less, indicating that the ice cream prepared with the aggregate sample was sweeter but had a lighter aftersweetness, better simulating the sweetness of sucrose. Furthermore, the experimental sample exhibited less bitterness and off-flavor. Overall, the panelists generally preferred the ice cream prepared with the aggregate sample, indicating that the steviol glycoside aggregates prepared in the present invention offer superior flavor when used in semi-solid foods compared to commercially available steviol glycosides.

[0120] Example 10:

[0121] Solid-state system sensory experiment:

[0122] Commercially available stevioside (powder, purity 95%), commercially available rebaudioside A (powder, purity 99%), and commercially available rebaudioside M (powder) were mixed in a mass ratio of 23:23:1 as a control sample, and the aggregate of Sample 4 in Example 4 was used as an experimental sample. First, 12 g of yeast and 6 g of white sugar were dissolved in 200 g of warm water (40°C) to obtain a yeast solution. Then, 1.2 g of stevioside, 30 g of white sugar, 1200 g of high-gluten flour, and 12 g of salt were weighed, transferred to a dough mixer and mixed evenly, and then the yeast solution, 240 g of egg liquid, and 150 g of milk were added, and the dough was kneaded at a slow speed for 5 minutes. , then switched to the fast dough kneading mode until the dough was chewy, soft and elastic, then 120g of butter was added, the dough was taken out, covered with film and allowed to rise at 25°C until the volume doubled, then the dough was taken out, kneaded to exhaust, shaped, and baked (upper fire 160°C / lower fire 210°C) for 15 minutes to obtain butter bread. Subsequently, a sensory evaluation panel (30 people, including 16 women and 14 men, aged 22 to 36) evaluated the color, elasticity, taste, sweetness, bitterness and odor, and overall preference of the butter bread samples, with a full score of 10. The results of the solid-state system sensory test are shown in the following table:

[0123] Table 10 Sensory test results of solid state system

[0124] Table 10 shows that compared to commercially available steviol glycosides, the butter bread prepared using the stevioside aggregates of the present invention showed no significant differences in color, elasticity, or mouthfeel, indicating that the physical structural modification of the steviosides by the present invention had no effect on the bread's preparation (appearance or texture). Regarding the taste of the butter bread, the experimental sample exhibited a higher sweetness level and significantly reduced bitterness and off-flavor, resulting in a higher overall preference for the sample. This demonstrates that the aggregates effectively improve the sweetness of solid bread foods, making them more popular with consumers.

[0125] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A steviol glycoside aggregate, characterized in that: It has a fibrous structure assembled from steviol glycosides; The steviol glycosides include the following components in percentage by mass: Stevioside or / and rebaudioside A: 80%~99.9%; Other steviosides: 0.1%~20%.

2. The steviol glycoside aggregate according to claim 1, characterized in that: The length of the stevioside aggregate is 10 μm to 200 μm, and the diameter is 0.2 μm to 5 μm.

3. The steviol glycoside aggregate according to claim 1 or 2, characterized in that: The other steviol glycoside is at least one of rubusoside, rebaudioside B, rebaudioside D, rebaudioside E, rebaudioside M, dulcoside A, and stevioside.

4. A method for preparing a stevioside aggregate according to any one of claims 1 to 3, characterized in that: The method comprises the following steps: dissolving stevioside in water to prepare a stevioside solution with a mass fraction of 0.5% to 30%, assembling the stevioside solution at a temperature of 10 to 80°C and standing or mechanically disturbing the solution, and then centrifuging and drying the stevioside aggregates.

5. The preparation method according to claim 4, characterized in that: The pH of the stevioside solution is 1.5-10.

0.

6. The preparation method according to claim 4 or 5, characterized in that: The stevioside solution also contains at least one of inorganic salts, polysaccharides and proteins.

7. The preparation method according to claim 4 or 5, characterized in that: The mechanical disturbance is one of electromagnetic stirring at a stirring rate of 50 rpm to 1500 rpm, shear homogenization at a shear rate of 1000 rpm to 20000 rpm, and ultrasonic homogenization at a power of 25 W to 400 W; and the assembly time is 0.5 h to 120 h.

8. A sweetener, characterized in that The invention comprises the steviol glycoside aggregate according to any one of claims 1 to 3.

9. A food, characterized in that The invention comprises the steviol glycoside aggregate according to any one of claims 1 to 3.

10. A method for improving the sweetness properties of steviol glycosides, characterized in that: The following steps are involved: Stevioside is assembled from structures without specific morphology into aggregates with fibrous structures.

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